What if genetics and fertility worked differently?

It used to be taught and so far as I can tell is still taught that the bigger and more diverse a gene pool, the total genetic content of a population, and the more thoroughly it is mixed, the better.

I do not scream.  I promised I would not be strident.  But my body language betrays me.  I tap with my index finger.  I thumb my nose.  I stand on my head and put my tongue out.  I turn, lean over and … well maybe not quite that far.  But I convey a subtle air of disappointment in human cognitive resource.  That idea is just stupid.  Come, let us reason together.

Consider a wild environment teeming with life.  If it is not in overall equilibrium, come back later when it is.  Now there are many forms of life, ranging from microbes to top predators, from algae to great trees.  We are not interested in the microbes; we are interested in complex life forms.  So take some middling animal, probably not the fiercest.  And this animal we shall assume is an example of the received wisdom that the bigger more diverse population is better.  Across time, this animal is roughly constant in number, the population is balanced with the other living things in the rich tapestry of interaction that is life.  Food supply, predators, disease, places to hide, disease pressure, temperature, water, altitude and every other living thing in the vicinity keep the animal balanced with others. 

Now we assume a bad stretch for the animal.  Any single one of the myriad of factors that impact it puts it at some small but significant disadvantage.  The population density falls.  That means the reproductive rate of the animal falls, since reproduction is the only conceivable interpretation of “better” in the concept “the bigger the better.”  It must mean “the smaller the worse,” and the population just got smaller.

Not much else changes.  There may be a trifling increase in food supply, but whatever hit the animal we are interested in might well have hit the food supply, too.  At all events the food, locked as it is in its own stitch in the tapestry, has its own problems.  The trifling decline in the numbers of our own animal has little impact.  So nothing changes.

In time, the original insult, whatever it was, wears off.  Our animal could not exist in its original numbers.  But it cannot get there.  It is in exactly the same environment with one change.  It is less fertile.  So its numbers, were we to take the premise seriously, must fall further.  Sorry.  There is no other thing that can happen.  So hippety hoppety slippety sloppety flippety floppety smush the animal descends along the curve of fertility and population size, which in the premise we are examining flatly requires that the smaller population is worse for ever and for ever, until the animal goes extinct. 

No some other species in the environment find the change a bit of a problem, and the process begins for that species too. 

Would it happen?  Do hard times occur?  Of course they do.  Disasters occur regularly, predictably, inevitably, frequently.  If the principle that the bigger and more diverse the gene pool size the better had ever been the general rule, then complex life would have vanished in a period spanning decades or possibly centuries.  Perhaps a few great trees might stretch into the next millennium, but that is just because some trees can live such a long time. 

All effort that went into proving that a computer model can confirm so much about the genetics of fertility was really unnecessary.  A moment’s thought should have been enough.  One can only wonder what an outsider looking at us would think.

I mean suppose we do it.  Suppose we take seriously the fact that whom we marry is important.  Suppose we turn around our present plunge toward extinction as a civilization if not as a species.  Suppose we do the job so well that our descendents are able to look back in their own history and accurately know what we are now doing.  What will our reward be?  They are going to think we have been unbelievably stupid.  They will wonder how anybody could ever accept for a moment that stirring up a gigantic and exceedingly diverse gene pool was a tolerable idea.  They will ask questions like, “What were they thinking?”  “Didn’t they notice that this never happens in nature?”  “At least didn’t they notice that there had never been an effective population size in the billions before?”  “What early line of reasoning convinced them it could be safe?”

That would be small thanks, it seems to me, for making the gigantic effort it will require to retool our social routines completely, revise our thinking in the most profound way, and forgo an enormous amount of wealth that we will sacrifice if we stop making money the only serious issue in life. 

And alas, they will make movies about it.  And the movies will have to have bad guys.  And many who are now alive will be depicted in very unfavorable lights. 

It isn’t fair, of course.  The number of people who had business to consider this and think about it carefully is too great to count, much less to dramatize.  But villains they are going to find.  And they are going to feel very smug and self righteous when they think about what fools we have been.

Sorry.  People aren’t going to change that much.  It’s going to be a cost of doing business. 

As of 6/28/2008 there have been 30 visitors to the site.  This is research, not advice.  Linton Herbert

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